In Q2 2009, Shire came down to earth: Revenues tumbled 18 percent to $630 million, following a 77 percent decline in sales of Adderall to $67.4 million from $296 million the year before. Vyvanse sales only earned $114 million in sales -- less than half the drug it was intended to replace.

Worse, Vyvanse earned $117 million in Q1, so sales there are actually flat -- and that's from the period before generic Adderall, marketed by Teva -- came in.

Now, the company is telling investors to wait until the back-to-school season starts, when parents put their kids on meds. Will it work? Perhaps. But the fact that the company is promoting Vyvanse for adults means the school thing is irrelevant. If Vyvanse is to replace Adderall it would have to more than double its sales base in the face of generic headwinds.